1. Field of the Invention:
This invention relates to an electronically controlled sample warper capable of warping a plurality of warp yarns simultaneously. In the warper, a plurality of warp yarns can be concurrently wound on a warping drum with omitting a yarn exchanging step to eliminate any time loss for the yarn exchange, thus reducing the warping period of time.
2. Description of the Related Art:
Conventional electronically controlled sample warpers are exemplified by Japanese Patent Laid-Open Publication No. 62942/1987, which generally comprises: driving and driven shafts 2, 3 projecting centrally from opposite ends of a hollow shaft 1 cantilevered at the driving-shaft side; a first small gear 5 loosely mounted on the driving shaft 2 and fixed to a pulley 4; a second small gear 7 loosely mounted on the driven shaft 3 and fixed to a yarn introduction lever 6; third and fourth small gears 9, 10 mounted on opposite ends of an auxiliary shaft 8 extending through the hollow shaft 1 and meshing the first and second small gears 5, 7, respectively, to cooperate with each other; drum frames 13, 14 mounted on the driven-shaft side of the hollow shaft 1 and each having an outer periphery having alternately an arcuate portion 11 and a straight portion; a pair of rollers 15 disposed one on the arcuate portion 11 of each of the drum frames 13, 14; and a warper drum A loosely mounted on the hollow shaft 1 and having horizontal beams 16 carrying the rollers 15 around which conveyor belts 17 are wound. The conveyor belts 17 are simultaneously driven to a common amount of fine movement by a drive member 21 threadedly engaged with interior screw shafts 20 of planetary gears 19 meshing with a sun gear 18 suitably driven from the exterior; as the sun gear 18 rotates, the planetary gears 19 rotates concurrently. The distal end of the yarn introduction lever 6 is bent inwardly to provide an yarn introducing part 6' disposed adjacent to the front end of the outer periphery of the warper drum A. The warper also includes: a shedding means for forming a shed and a cut shed by selecting warp yarns (to be wound on the warper drum) over and under shedding bars and cut shedding bars; a total yarns counter count means for rendering an up signal, of a total counter for counting the total number of the warp yarns, to be on or off; a total yarns completion termination means for terminating the operation of the warper when the total number of the warp yarns reaches a predetermined value; a conveyor belt leftward moving means for moving the conveyor belt leftwardly; a conveyor belt rightward moving means for moving the conveyor belt rightwardly; an operation/termination means for transmitting the rotation of a main motor 46 to the yarn introduction lever 6; a yarn selection means for controlling a yarn selection guide 27 and a yarn removing unit 32; a yarn pressing solenoid means for rendering a solenoid of a yarn relaxation preventing (yarn pressing) unit 60 operative and inoperative; and a windings count means for counting the number of windings of the yarns and for displaying the counted result. By selecting the kind of yarn 0-n, and setting the number of yarns, the number of repeats, the number of windings, the quantity of movement of the conveyor belt, a desired pattern of warping can be achieved automatically. The reference numerals used here are similar to those used in an embodiment of this invention described below.
However, in this conventional warper, since an ordinary motor is used as the main motor, it is impossible to vary the rate of rotations during operating so that miscatches and mischanges as well as yarn breakage are inevitable when exchanging yarns. And it is impossible to terminate relaxing and to perform jogging, thus causing only inadequate operating efficiency. For setting the density of warp yarns, the rate of moving the conveyor belt is determined by varying the gear ratio of speed change gears operatively connected to the main motor Since the conveyor belt is moved even during idling, regular windings of yarns on the warper drum are difficult to achieve so that the tension and the warp length would finely vary during. In order to overcome the abovementioned problems, proposals have been made to employ an inverter motor or an AC servo motor in the warper (Japanese Patent laid-Open Publications Nos. 35845/1988 and 35846/1988).
However, in the last-mentioned conventional warpers, since always only a single yarn is engaged on the yarn introducing part, it is impossible to wind two or more yarns concurrently on the yarn introducing part. Further, since the main motor is reduced in speed and idled one or two times, during exchanging yarns, in order to avoid miscatching, mischanging, or other misoperating, the warping operation is wasteful in part. Yet assuming that two or more yarns are engaged on the single yarn introduction part in order to omit this yarn exchanging step, two or more yarns could be wound on the warper drum, but alternate an accurate selection of yarns one at a time for the shedding bar and the cut shedding up and down is impossible.